Electrical connector

ABSTRACT

A pair of complementary surfaces are connected together electrically by compressing between them a connector formed of a resilient metal strip having a pair of longitudinally extending and longitudinally corrugatedly contracted side portions interconnected by a plurality of transversely extending parallel tongues or contact lamellae each having one end connected to one side portion, another end connected to the other side portion, and a middle waist region substantially wider than said ends. The side portions may be sinusoidally corrugated or may be formed as a succession of flattened loops.

United States Patent [1 1 Neidecker 1 1 ELECTRICAL CONNECTOR [75]Inventor: Rudolf Neidecker, Basel,

Switzerland [73] Assignee: Multi-Contact A.G., Basel,

Switzerland [22] Filed: Aug. 29, 1973 [21] Appl. o; 392,517

[30] Foreign Application Priority Data Sept. 1, 1972 Germany 2243034[52] US. Cl....... 339/272 R; 339/252 R; 339/263 L [51] Int. Cl. H0117/08 [58] Field of Search 151/3, 35, 36; 174/94 S, 174/356 S; 339/95 R,95 A, 95B, 252, 263, 272 R, 277

[56] References Cited UNITED STATES PATENTS 2,217,433 10/1940 Crabbs339/95 R UX 3,453,587 7/1969 Ncidecker 339/95 A FOREIGN PATENTS ORAPPLICATIONS Germany 339/263 L July 22,1975

531,701 1/1941 United Kingdom 151/35 Primary Examiner-Roy D. FrazierAssistant Examiner-Lawrence .l. Staab Attorney, Agent, or Firm-Karl F.Ross; Herbert Dubno [57] ABSTRACT A pair of complementary surfaces areconnected together electrically by compressing between them a connectorformed of a resilient metal strip having a pair of longitudinallyextending and longitudinally corrugatedly contracted side portionsinterconnected by a plurality of transversely extending parallel tonguesor contact lamellae each having one end connected to one side portion,another end connected to the other side portion, and a middle waistregion substantially wider than said ends. The side portions may besinusoidally corrugated or may be formed as a succession of flattenedloops.

7 Claims, 5 Drawing Figures SHEET PATENTED JUL 2 2 I975 PATENTED JUL 2 2ms SHEET ELECTRICAL CONNECTOR .CROSS REFERENCE TO RELATED APPLICATIONSThis application is related to my copending and commonly assigned patentapplications Ser. Nos. 335,715 (now U.S. Pat. No. 3,845,451) and Ser.No. 336,033 (now U.S.-Pat. No. 3,828,301) both filed Feb. 26, 1973.

FIELD OF THE INVENTION The present invention relates to an arrangementfor forming an electrical connection between two surfaces. Moreparticularly this invention concerns an electrical connector forinterconnecting two bus bars or the like.

BACKGROUND OF THE INVENTION It is known to form an electrical connectionbetween two complementary surfaces with a contact sheet or strip asdescribed in U.S. Pat. No. 3,453,587 issued July 1, 1969 which is astrip of resilient metal formed with a plurality of parallel slits thatsubdivide its central region into a plurality of parallel tongues orcontact lamellae extending between coplanar side portions. These tonguesare twisted to lie at an angle to the plane of the side portions. Such aconnector is compressed between the two complementary surfaces,resiliently deforming the lamellae so as to make a very good electricalconnection.

One of the factors which influences the electrical resistance offered bysuch a connector is the force with which the lamellae bear on thesurfaces; the greater the force the less the resistance. Another factoris the number of lamellae since each lamellae only bears with one edgeon one surface and with its other edge on the other surface. Acompromise must be made between these two factors since, if the numberof tongues or lamellae is increased by decreasing the width of theselamellae, the force which the tongues exert on the surfaces is alsodecreased as their capacity for elastic deformation is decreased, andvice versa.

It has been suggested that the current-carrying capacity of such aconnector can be increased, and the resistance decreased, by providing apair of such connector sheets whose tongues project more above one faceof the sheet than above the other. Two such sheets are used on top ofone another, with the tongues of one sheet projecting through the other.Such an arrangement is twice as expensive as the above-described system,but presents a substantial increase in currentcarrying capacity. Inaddition such an arrangement takes up significantly more space betweenthe surface, and is for other reasons often undesirable.

OBJECTS OF THE INVENTION It is therefore an object of the presentinvention to provide an improved electrical connector of theabovedescribed general type.

Another ojbect is the provision of such a connector which has greatercurrent'carrying capacity and lower resistance to electrical currentflow than the prior-art devices.

SUMMARY OF THE INVENTION These objects are attained according to thepresent invention in a connector of the above-described general typewherein the side portions are longitudinally corrugatedly contracted. Bythis it is meant that these portions have a developed or extended lengthwhich is substantially greater than the length of the contracted strip.This effect is achieved according to a feature of this invention bycorrugating or wrinkling the side portions.

In accordance with other features of the invention the tongues havemiddle regions which are substantially wider than their ends. Thus thesetongues are formed in an initially flat metal sheet by punching outslots having a dumbbell profile, i.e. wider at the ends than at thecenter. The number of tongues per unit length in such a connector issubstantially increased so that the conductivity across it is alsogreatly increased.

The longitudinally contracted sides can be formed with sinusoidalcorrugations. It is also possible to form them as a succession offlattened loops, this being effected by crimping or wrinkling the sideportions, then flattening them without allowing them to extend.

Such a connector can be used between two flat or curved surfaces. It ispossible to apply a ring or disk connector of this type to a plugconnector or the like, or conform it to any other desired shape.

DESCRIPTION OF THE DRAWING The above and other objects, features, andadvantages of the present invention will become more readily apparentfrom the following description, reference being made to the accompanyingdrawing in which:

FIG. 1 is a perspective view of a pair of bus bars connected togetheraccording to the present invention;

FIG. 2 is a top view of the lower bus bar of FIG. 1;

FIGS. 3 and 4 are perspective views of two embodiments of the connectoraccording to the present invention; and

FIG. 5 is a top view of a connector according to this invention prior tocontraction of its side portions.

SPECIFIC DESCRIPTION As shown in FIG. 1 a connection 1 is formed betweena pair of flat bus bars 2 and 3 by interposing therebetween a pair ofgenerallly flat connectors 4. A bolt 8 between the two connector strips4 serves to secure these two bars 2 and 3 together and compress thestrips 4. The strips are held by longitudinal slots at their edges witha spacing less than the width of the strip.

As shown in FIGS. 2 and 3 each strip 4 comprises a pair oflongitudinally corrugated side portions 7 formed with transversecorrugations 9 and joined together by tongues 5 which are wider at theirmiddle regions 5' than toward their ends 5". Slots 6 of dumbbell shapeas shown in FIG. 5 in an noncontracted strip are formed in the originalmetal strip to give these tongues 5 the widened waist 5'. The tongues 5are also twisted about their longitudinal axes, that is, transverse tothe longitudinal direction of the strip 4 as shown by arrow A, which isthe direction of contraction of the side portions 7.

FIG. 4 shows a strip 4' which has side portions 7' formed as asuccession of overlapping loops 10, which are formed by crimping orwrinkling the portions 7' as in FIG. 3, then flattening the corrugationsin one direction while preventing the strip 4 from extending. This givesthe strip 4 a fixed length. Here the extent of overlap of the loops 10determines the extent of contraction, in FIG. 3 the determining factoris the height of the crests of the corrugations 9. In both cases it iseasy to produce connector strips of almost any desired conductivity. Iclaim:

1. An electrical connector for electrically interconnecting twosurfaces, said connector comprising a planar conductive metal sheethaving a pair of generally coplanar longitudinally extending andlongitudinally corrugatedly contracted side portions, the extendedlengths of said side portions exceeding the length of said sheet alongsaid side portions, and a plurality of parallel transverse resilienttongues extending between said portions and twisted from the plane ofsaid portions, said tongues having ends joined to said sides and middleregions wider than said ends, said side portions being uniformlycorrugated over their entire lengths and having more than onecorrugation per tongue.

2. The connector defined in claim 1 wherein said side portions areformed with corrugations extending traversely, 1

3. The connector defined in claim 2 wherein said side portions areformed with a plurality of longitudinally succeeding loops.

4. The connector defined in claim.3 wherein said loops are flattened.

5. The connector defined in claim 1 wherein said surfaces are juxtaposedfaces of a pair of flat plates sandwiching said sheet between them, saidconnector further comprising means urging said surfaces together againstsaid sheet.

6. The connector defined in claim 5 wherein said means is a bolt passingthrough said plates.

7. The connector defined in claim 6 wherein a pair of such sheets in theform of strips are disposed on opposite sides of said bolt. v

1. An electrical connector for electrically interconnecting twosurfaces, said connector comprising a planar conductive metal sheethaving a pair of generally coplanar longitudinally extending andlongitudinally corrugatedly contracted side portions, the extendedlengths of said side portions exceeding the length of said sheet alongsaId side portions, and a plurality of parallel transverse resilienttongues extending between said portions and twisted from the plane ofsaid portions, said tongues having ends joined to said sides and middleregions wider than said ends, said side portions being uniformlycorrugated over their entire lengths and having more than onecorrugation per tongue.
 2. The connector defined in claim 1 wherein saidside portions are formed with corrugations extending traversely.
 3. Theconnector defined in claim 2 wherein said side portions are formed witha plurality of longitudinally succeeding loops.
 4. The connector definedin claim 3 wherein said loops are flattened.
 5. The connector defined inclaim 1 wherein said surfaces are juxtaposed faces of a pair of flatplates sandwiching said sheet between them, said connector furthercomprising means urging said surfaces together against said sheet. 6.The connector defined in claim 5 wherein said means is a bolt passingthrough said plates.
 7. The connector defined in claim 6 wherein a pairof such sheets in the form of strips are disposed on opposite sides ofsaid bolt.